NOSToc. 289 



of iV. commune, but the filaments are different, being much 

 smaller iu size, although, Hkc those of N. commune, distinctly 

 moniliform. 



3. NoSTOC FOLIACEUM Ag. 



Plate LXXVI. Fig. 2. 



Char. Fi'ond membranaceous, erect, plaited, olive green. 

 Filaments slender, copious, moniliform. Enlarged globuli 

 numerous, 

 Nostoc foliaceum Ag., Syst. p. 19. ; Ilarv. in Hook. Br. 

 Flora, ii. p. 399. ; Harv. in Manual, p. 184. ; Meneghini, 

 INIouographia Nostochinearum Italicarum, vol. v. p. 18. 

 seric ii. delle ]\Iemorie della E. Academic delle Scienze 

 di Turino. 

 Hah. On clayey ground kej^t constantly damj) by the 

 oozing of water, Appin : Capt. Cai'michael. Ireland : 

 Mr. Moore. 



** This species is easily distinguished both by its appearance 

 and station from Nostoc commune, to which it seems similar, 

 as respects certain external characters. It never swells up 

 into the form of a vesicle ; the structure, altogether uniform, 

 extends as a membrane, and rises up by moisture into plicated 

 lobes : it grows on stones, and is evolved, the winter scarcely 

 being ended, when Nostoc commune has not yet appeared."' — 

 Menegh. The difference in the size of the filaments of Nostoc 

 commune and N. foliaceum is perhaps the only character 

 whereby the two species can at all times be discriminated, 

 the threads being much smaller in the latter species. 



4. Nostoc srniEEicuM Vauch. 

 Plate LXXYI. Fig. 5. 

 Char. Frond small, globose, densely aggregated, solid, smooth, 

 olive green, waterg within. Filaments small, moniliform. 

 Nostoc sjdmricum Vauch., Conf. p. 223. pi. xv. f. 2, 



